A game device is known which is designed such that a field object with a preset transparency flag of 1 is rendered by using mask data obtained by rendering a circular mask region around the position of a character object projected on a plane, while a character object and a field object with a transparency flag of 0 are rendered by an ordinary method (see Japanese Patent Application Publication No. 2006-68138).
A game device is also known which is designed such that, when relative positions of objects with respect to a view point varies, a virtual image containing the objects is rendered by referring to information indicating transparency of the objects, while updating, every unit time, information indicating a transparency of any object that is determined to be located at a distance smaller than a predetermined distance from the viewpoint in the virtual space, so that the transparency of the object is increased gradually (see Japanese Translation of PCT Application No. 2008-43589).
There is a technology called AR (Augmented Reality) wherein a real space image received from a camera is displayed in a far-side layer of a display facing the opposite direction from the imaging direction of the camera, while displaying, in a near-side layer, information according to the directions of the camera and the display, and a current position calculated based on input from a GPS (Global Positioning System), an acceleration sensor or an angular rate sensor, whereby the real space information displayed in the display is augmented.
However, such technology is only designed to augment the volume of information that a user can obtain from the real space by displaying the information on top of the real space image, and is not designed to augment the space recognized by the user.
In view of the problems described above, an object of this invention is to make it possible to augment the space recognized by a user and to enhance the effects of augmented reality.